Sheet and plate work gripping apparatus having angularly adjustable grippers



May 27, 1 5 L. R. GRAY ET AL ,835,947

SHEET AND PLATE WORK GRIPPING APPARATUS HAVING ADJUSTABLE GRIPPERS ANGULARLY 5 Sheets-Sheet 1 Filed June 8, 1954 Q s Em m May 2 1958 L. Ran/w 21w. 2,835,947

' SHEET AND PLATE WORK GRIPPING APPARATUS HAVING ANGULARLY ADJUSTABLE GRIPPERS Filed June 8, 1954 I 5 Sheets-Sheet 2 5'92. fip i v 071 9/7/0/5: Landon 1Q. Gra y 7. Blair Hawkes 9% y M S R. GRAY ET AL SHEET AND PLATE WOR May 27, 1958 2,835,947

K GRIPPING APPARATUS HAVING ANGULARLY ADJUSTABLE GRIPPERS 5 Sheets-Sheet 3 Filed June 8, 1954 [n van/ans.- Lanb/on A. Gray 7. 5/a/ 'r Hawkes by I A/f'ys L. R. GRAY ETAL 2,835,947

ANGULARLY ADJUSTABLE GRIPPERS V 5 Sheets-Sheet 4 MQNMRWM RAM 1 May 2,7, 195&

SHEET AND PLATE WORK GRIPPING APPARATUS HAVING Filed June 8, 1954 /m/enfors: tan don 9. Gray 7. Blair Hawkes y 6 Affys 2,835,947 SHEET AND PLATE WORK GRIPPING APPARATUS HAVING S R E P n w T :m m

m RY m A L U G N A May 27, 1958 5 Sheets-Sheet 5 Filed June 8, 1954 me/wo s: Lanaon A Gra y 7." Blair Haw/res icide with this contour. the work, arranged as described, are disclosed by the :Oeckl Patents 2,123,683 and 2,269,549, respectively, is *suedJuly 12, 1938 and January 13, 1942, and by the KuhnerPatent 2,129,774, issued September 13, 1938. ".Asishown by these'patents, the jaws may move relative United States Patent SHEET AND PLATE WORK GRIPPIN G APPARATUS HAVING AN GULARLY ADJUSTABLE GRIPPERS Application June 8, 1954, Serial No. 435,297

4 Claims. (Cl. 24-81) Thisinvention relates to an apparatus for connecting sheet and plate work to a tensioning device. The aprparatus is particularly intended for use with .a stretch "forming machine requiring gripper jaws for gripping the opposite ends of the work so that the work may be wrapped around the die or form block and tension stretched beyond its elastic limit.

T:'he stretch forming machine art is a very old one Y and long ago it was recognized that when the die or form block has a contour transverse to the work which is .anything but linear it becomes desirable to grip each end of the work with a plurality of jaws arranged so .thatthe .grip ends of the work may'follow it or coin- Multiple jaws for each end of to the die or form block or may tension the work by being anchored while the die or form "block is moved 1 relative to .thejaws. Thewjaws, at "each work gripping station, are arranged so that they may grip the work when the latter. is transversely bent or curved so that when the die or form block is contoured to transversely "bend or curve the sheet and plate work it is unnecessary to have 'longspansbetween the gripper jaws and the die or form block solely for the purpose of accommodating 'a transitional contour change from the bent 'or curved shape to a' linear shape as would be required if the .gripper jaws were entirely linear in their grippingaction transversely 'with respect to the work.

One of the objects of the present invention is to im- ,:prove on such constructions so -as to provide, for each end of'the Work, an apparatus'i'n the form of'an assembly -of-jaws which may be made individuallywith amassive and-strong construction and which may be adjusted angularly with respect'to each other so as to accommodate the transversely bent or curved work in a manner more. convenient and practical than has heretofore been providedby-the art. Anotherobject is to provide such an apparatus in aform which will provide for bending or curving the work transversely regardless of 'Whth61 I-110il the work has actually been engaged .with the die or form block, whereby a flat piece of panying drawings and hereafter described as to both its parts, construction and operation.

This gripper'jaw assembly or apparatus 'is illustrated by the accompanying drawings in which:

Fig. l is a front view, meaning the side'facing "the w'or-k'whi'ch extends away from the: gripperjaws;

2,835,947 Patented May 27, 71958 Fig. 2 is a side view of Fig. 1;

'Fig. 3 is a longitudinal section taken on the line 3-3 in Fig. 1;

Fig. 41s a longitudinal section taken on the line 4-4 in Fig. 1;

' Fig. 5 is a cross section taken on the line 55 in Fig. 2;

Fig. 6 is a cross section taken on the line 66 in Fig. 2;

Fig. 7 is a longitudinal section taken on the line 77 in Fig. 5;

Fig. 8 is an elevation'taken on the line 88 in Fig. 7;

Fig. 9 is a longitudinal section taken on the line 9-9 in Fig. 5;

Fig. 10 is an elevation taken on the line -1010 in Fig. 9;

Fig. 11 is a schematic front view showing the jaws shifted to accommodate a curved sheet or plate; and

Fig. 12 diagrammatically shows themanner in which the pivotal points shifted in Fig. 11.

Referring to these drawings, the apparatus illustrated includesa transversely extending series of jaws 1, 2, 3 and 4.having.1nouths 5, 6, 7 and 8, respectively, which open forwardly to receive and grip the work. These jaws are duplicates of each other and each has a lower and immovable work gripping surface 9 and an upper, verticallyreciprocative, work grippingsurface 10, the jaw :10 being provided with an hydraulically powered actuating mechanism generally shown at 11. The surfaces 9 and-ltl extend'the full width of the jaw in each instance. The parts 9, 10 and 11 are duplicates in all instances and, therefore, similar numerals are used to indicate the'selpartsfor all of the jaws.-

The mount12is 1ocatedbehindthe jaws and is adapted for connection to thetensioning device, as by being provided with a'shank 13. This shank connects with the stretch formingpress tension cylinders and this may or may not be done so that the illustrated assembly may be rotated about the'axis .of the shank 13. The mount 12 is a transversely extending mount somewhat in the nature of a cross head, and two transversely extending platens 14 and 15 are located in front of this mount 12. The longitudinally extending transversely spaced pivots 16 and I7 connect the platens to the mount 'so that the platens may be transversely aligned and angularly misaligned with respect to each other. These pivots 16 and 17 'mu'stbe massive'enough to carry the work stretching tension.

Linear guideways 18 and 19 are positioned on the fronts of the platens'14 and 515, respectively, so as to extend longitudinally 'with respect to the latter in each instance. Thesezguideways are illustrated as comprising undercut grooves formed in the fronts of the platens.

Each of the 'fourjaws -1 through 4 is provided with a shoe, numeraled 20 through 23 which is slidably secured 'to and guided by'theone of the vguideways 18 and 19 which is behind the jaw and a longitudinally extending pivot, 'numeraled 24 through 27 connects each jaw to its shoe.

The mutually adjacent sides of the jaws 1 through 4 have longitudinally extending pivots 28 through 30 connecting them together.

'two'jaws, inur'neraled 1 and 4, respectively clockwise and counterclockwise, because the four jaws have their rn'utually' interfacing surfaces above the pivots 28 through .AQAF

30 formed with flat surfaces, indicated by the numeral 31 in all instances, whichabut mutually so as to etfect the alignment described. These mutually interfacing surfaces below the pivots 28 through 30 in allinstances have receding or angular surfaces 31a so that the various jaws may be rotated throughout a range of'im'otions opposite to those effecting the mutual alignment, without these angular surfaces 31a abutting.

The mount 12 has an upstanding and forwardly slanting bracket 32 fixed to it centrally and hydraulic jacksl33 and 34, respectively, extend oppositely and downwardly so as to connect the upper end of this bracket 32 with short upstanding brackets 35 and 36 fixed to the tops of the jaws 1 and 4, respectively. The jacks 33 and 34 are double acting so that theymay be retracted so as to rotate the jaws 1 and 4 as required to mutually align the series of jaws, or either one or both the jacks may be pushed outwardly to misalign the jaws. The pivot 29 is anchored with respect to the mount 12 by a system of levers 37 and 38. The pivot 29 is anchored against transverse shifting but may move vertically.

As shown in Figs. 7 and 8 the pivots 28 and 30, which duplicate each other in construction, each comprises the pivot pin itself and an inner plate 39 fastened to one of the two jaws and an outer plate 40 fastened to the other of the two jaws, the two plates overlapping and the pivot pin passing through both. The entire pivot assembly is located in a recess 41 formed cooperatively by the two mutually adjacent jaws and the pivot pin 28, or 30, is short enough so that everything is flush respecting the back surfaces of the jaws. The pivot 29 is in the form of a pivot pin and similar plates 39a and 40a are used together with a recess 410. However, in this instance the pivot pin 29 extends backwardly, which is possible because it is located between the inner ends of the two platens 14 and 15, and this projecting end is enlarged by a washer 42, a hole being formed through both the washer and the end of the pin so as to receive a transverse bar 43 which pivotally interconnects the pin 29 and the lower end of the lever 37. The levers 37 and 38 widen gradually upwardly so as to provide for good lateral rigidity.

The shoes 20 through 23 fit in the undercut portions of the guideways 18 and 19, and the various pivot pins 24 through 27 are anchored longitudinally with respect to both their shoes and the jaws with which they are associated. The entire construction of the apparatus is such that the heavy tension, required to stretch form the work, may be carried longitudinally through all of the various interconnected parts which obviously must carry this stress.

It is to be noted that the platens, shoes, pivot pins and the like provide means for connecting the jaws to the mount so that with respect thereto the jaws are pivotal on longitudinally extending axes permitting the jaws to transversely align and angularly misalign with respect to each other and which axes are shiftable transversely towards and away from each other and arcuately around a longitudinally extending axis which is fixed with respect to the mount. This applies to either of the two outer jaws, the shiftable axes being provided by the pivots 24 and 25, and the fixed axis is formed by the pivot 16, insofar as the jaws 1 and 2 are concerned. As to these two jaws it is to be noted that all of the axes of the pivots are aligned transversely.

In the case of the entire assembly, there are two of the above systems or organizations, and where they abut, which is between the two innermost jaws 2 and 3, the pivot 29, which interconnects these two jaws, is anchored transversely or laterally with respect to the mount 12. 1

One phase of the operation of the device, respecting its ability to conform with transversely bent or curved work, is shown by Figs. 11 and 12. Here both jacks 33 and 34 have been jacked out to rotate the jaws 1 and 4 outwardly with respect to each other. With this action the jaws may be made to define four chords of the are desired.

So as to predetermine the configuration obtained by the jaws, adjustable struts 44, 45 and 46 are located between each two adjacent ones of the series of jaws. These struts pivotally connect between brackets 47 through 50 centrally positioned on the bottoms of the fronts of the jaws 1 through, 4 respectively. Each strut has an adjustable abutment 51, 52 and 53, respectively, for the three struts 44 through 46. These abutrnents may be individually adjusted to limit the transverse pivoting or hinging action of any two jaws relative to each other. Thus, the abutment 51 butts the bracket 48, the abutment 52 butts the bracket 49 and the abutment 53 butts the bracket 50, when the jaw 1 is rotated counterclockwise and the jaw 4 is rotated clockwise, with consequent rotation of the jaws 2 and 3. When adjusted substantially as shown in Fig. 1 the curve contour of Fig. 11 is obtained when the jacks 33 and 34 are extended by appropriate use of hydraulic pressure.

It is, of course, possible to keep one of the jacks contracted by hydraulic pressure while hydraulically extending the other so as to form two chords of a half curve. It is clear that many configurations are possible and that they may extend generally horizontally or vertically if the part 13 is mounted so that the entire assembly may be rotated, this including the mount 12.

The jacks 33 and 34 provide powered means permitting even heavy gauged or thick sheet or plate work to be transversely bent or curved by power even before the work is brought against the die or form block. It is to be understood that two of the assemblies will ordinarily be used although it is conceivable that one of the assemblies may be used in conjunction with a rigid linear jaw system.

Each of the jaws is relatively wide transversely and, therefore, may be made extremely massive and strong. There are relatively few parts between each jaw and the tensioning device and all of these parts may be made large and strong. In spite of these advantageous features respecting size, the apparatus is adequately flexible to accommodate practically all possible contours of transversely bent or curved work. In most instances the possibility of forming four chords of the arcuate shape provide for adequate flexibility, but it is conceivable that a greater number of chords might be desired. These could be provided by redesigning so as to accommodate a. greater number of jaws.

No effort has been made to show the hydraulic circuits required to actuate the hydraulic jacks 33 and 34 or the various jaw actuating mechanisms 11. Needless to say the jaws must clamp the work with great firmness.

When either of the jacks 33 or 34 is actuated it not only rotates the outer one of the jaws associated therewith but also applies a downwardly directed force which tends to assist in the rotation of the one of the platens mounting the rotated jaw.

Fig. 12 is of particular interest since it emphasizes the fact that due to the geometry of the construction of the disclosed apparatus, the work cannot be stretched transversely between any of the series of jaws which engage the work. Each jaw pivots uniformly about its neighbor in alignment with the work gripping plane fixed by the design of the jaw. The work itself hinges beis true in the case where the jaws slide at right angles to the general plane of the work.

We claim:

1. Apparatus for connecting sheet and plate work to a tensioning device, said apparatus including at least four jaws arranged as a transversely extending series of jaws which open'forwardly so as to receive and grip the same piece of work, a mount located behind said jaws and adapted for connection to said device, and means for connecting said jaws to said mount so that with respect thereto the jaws are each pivotal on its own lngitu-.

dinally extending axis permitting the jaws to transversely align and angularly misalign with respect to each other, each outermost two of said axes being shiftable in each instance transversely towards and away from each other and arcuately about a longitudinally extending axis which is fixed, said fixed axes being transversely spaced outwardly from the central two of said shiftable axes when all of the latter are transversely aligned.

2. Apparatus for connecting sheet and plate work to a tensioning device, said apparatus including at least four jaws arranged as a transversely extending series of jaws which open forwardly so as to receive and grip the same piece of work, a mount located behind said jaws and adapted for connection to said device, and means for connecting said jaws to said mount so that with respect thereto the jaws are each pivotal on its own longitudinally extending axis permitting the jaws to transversely align and angularly misalign with respect to each other, each outermost two of said axes being shiftable in each instance transversely towards and away from each other and arcuately about a longitudinally extending axis which is fixed, said fixed axes being transversely spaced outwardly from the central two of said shiftable axes when all of the latter are transversely aligned, each two mutually adjacent ones of said jaws having transversely mutually abutting surfaces which are contoured to permit the jaws to mutually misalign angularly when relatively pivoted oppositely, means for pivotally interconnecting said jaws so that they pivot relative to each other on longitudinal axes located so as to be transversely substantially intersected by the planes in which the jaws grip the work, and powered means for pivoting the outermost ones of said jaws on its said shiftable axis.

3. Apparatus for connecting sheet and plate work to a tensioning device, said apparatus including a transversely extending mount adapted for connection to said device, two transversely extending platens located in front of said mount, longitudinally extending transversely spaced pivots connecting said platens to said mount so that the platens may be transversely aligned and angularly misaligned with respect to each other, linear guideways positioned on the fronts of said platens and extending longitudinally with respect thereto, said guideways being aligned when said platens are aligned, a plurality of jaws located in front of each of said platens and which open forwardly to receive and grip the work, and for each of said jaws a shoe slidably secured to the one of said guideways which is behind the jaw and guided thereby and a longitudinally extending pivot connecting said jaw to said shoe, the mutually adjacent sides of said jaws having longitudinally extending pivots connecting them together, the pivot interconnecting the adjacent end jaws on said platens being anchored against transverse shifting but being free to move vertically.

4. Apparatus for connecting sheet and plate work to a tensioning device, said apparatus including a transversely extending mount adapted for connection to said device, two transversely extending platens located in front of said mount, longitudinally extending transversely spaced pivots connecting said platens to said mount so that the platens may be transversely aligned and angularly misaligned with respect to each other, linear guideways positioned on the fronts of said platens and extending longitudinally with respect thereto, a plurality of jaws located in front of each of said platens and which open forwardly to receive and grip the work, and for each of said jaws a shoe slidably secured to the one of said guideways which is behind the jaw and guided thereby and a longitudinally extending pivot connecting said jaw to said shoe, the mutually adjacent sides of said jaws having longitudinally extending pivots connecting them together, means for limiting the pivotal action of each two adjacent ones of said jaws relative to each other, transverse jacks connected at one end to said mount at a substantially central location between said pivots connecting said platens to the mount and offset transversely from alignment therewith, and at their other ends to the outermost ones of said jaws at a location in each instance offset from the axis of the pivot connecting it with its said shoe, and means for anchoring one of said pivots connecting said jaws together to fix its transverse location with respect to said mount.

References Cited in the file of this patent UNITED STATES PATENTS A photograph of Gripping Jaws developed by North American Aviation Co., received in Div. 14 on January 23, 1952, hearing identification Numbers 88-31002-23 and 850-1341C. 

